Automated quilting has become increasingly popular because it allows persons to quilt who lack the time, skill, physical ability or patience to quilt by hand. Mechanized quilting frames provide for a sewing machine to be mounted on a sewing machine carriage which is movably mounted on the quilting frame. The sewing machine carriage typically has a pair of carriage motors, each motor being connected to a gear box which is connected to a carriage drive mechanism. The carriage drive mechanism interacts with the quilting frame, thereby providing for the two dimensional, x-y, horizontal movement of the sewing machine carriage and the sewing machine mounted thereon. This x-y horizontal movement of the sewing machine provides for the automated positioning of the sewing machine for the automated sewing of a pattern. The fabric layers being quilted are typically held on and between a pair of fabric rails, a feed rail and a take up rail, the take up rail passing through the throat of the sewing machine and the feed rail being positioned outside the throat of the sewing machine. The two fabric rails provide for the linear positioning and retention of the fabric and for maintaining a desired tension on the fabric as the sewing machine is moved in the x and y dimensions and sews a desired pattern.
A typical prior art automated quilting frame 4 is illustrated in FIG. 1. A sewing machine 1 mounted on a sewing machine carriage 2 and engaged in an automated sewing operation on a typical prior art quilting frame 4 is illustrated. The feed rail 3 and the take up rail 5 hold all the layers of fabric 7, alternatively referred to in this application as the “fabric”, in position as the sewing operation is under way. It will be noted on FIG. 1, that the y dimension movement 9 of the sewing machine in the y dimension 11 is limited by the machine throat length 13, which is the distance between the outside throat surface 15 and the inside throat surface 17. The throat length 13 is obviously structurally related to the arm length 19 of the sewing machine arm 21.
In FIG. 1, the sewing machine 1 is shown in maximum forward position 23. Referring also to FIG. 2, the sewing machine 1 is shown in its maximum rearward position 25. The maximum y dimension machine movement 27 is limited by the throat length 13. While the length of the mechanized quilting frame typically will accommodate the full width of the quilt and thereby allow for the x dimension movement of the sewing machine 1 in the x axis for the full width of the quilt, the throat length of a sewing machine obviously cannot be practically or economically increased to a dimension that would allow for the full length of the quilt to be deployed in the throat of the sewing machine.
The foregoing identifies a primary difficulty and limitation of known automated quilting systems. There have been a number of prior art methods and devices developed for attempting to deal with this difficulty and limitation, including, for example, devices providing for the automated scrolling of the fabric between a feed rail and a take up rail to provide for expanding the available effective y dimension movement. Some of the notable problems with such devices are fabric stretch and varying diameters of fabric roll on the feed rail and take up rail. Other prior art methods and devices are known which provide for dividing oversized embroidery patterns and for the segmented sewing of the patterns. A notable problem with such methods and devices is that they do not provide for the pattern adjustment that is required in consecutively sewed pattern segments to provide for an accurate match of pattern lines between segments and to provide for the preservation of the integrity of the overall pattern as sewed.
It is therefore an objective of the present invention to provide a method and apparatus for the automated sewing of an over-sized quilt pattern, or other sewing pattern such as an embroidery pattern, i.e., a sewing pattern that has a length that is greater than the available throat length of the sewing machine being used, or has a width that is greater than the maximum available lateral movement of the sewing machine.
It is a further objective of the present invention to provide a method and apparatus for the automated sewing of an over-sized quilt pattern or other sewing pattern that provides for the accurate sewing of complex, over-sized, sewing patterns.
It is a further objective of the present invention to provide a method and apparatus for automated sewing of over-sized sewing patterns that minimizes stitching error or mismatch.
It is a further objective of the present invention to provide a method and apparatus for automated sewing of an over-sized sewing pattern that operates with fabric positioned stationary on a feed rail or other feed mechanism and a take-up rail or other take-up mechanism during the sewing operation.
It is a further objective of the present invention to provide a method and apparatus for automated sewing of an over-sized sewing pattern by dividing the sewing pattern into pattern segments and providing for matching the stitching at the respective borders of the segments of the pattern, thereby preventing stitching mismatch at segmental borders.
It is a further objective of the present invention to provide a method and apparatus for automated sewing of an over-sized sewing pattern which provide for dividing the sewing pattern into pattern segments and provide for accurately matching of the stitching at the respective borders of the segments of the pattern, while preserving the integrity of the overall pattern, by adjusting the pattern lines in consecutively sewed pattern segments.